Superjunction semiconductor devices are well known and generally provide plural layers of P and N regions connected between a source and drain region. In order to turn the device on in a forward conduction direction, current flow can proceed, for example, through the N type regions, which have a relatively high N type concentration. Thus, the device has a relatively low on resistance per unit area, or RDSON. To turn the device off, the adjacent P and N regions are caused to fully deplete, thus blocking current flow and turning the device off.
Superjunction devices of these types are shown in U.S. Pat. Nos. 5,216,275 and 4,754,310, and are also shown in copending application Ser. No. 60/113,641, filed Dec. 23, 1998 (IR-1676 Prov) in the name of Boden, and assigned to the assignee of the present invention.